Weight control unit system for drilling rigs



April 5, 1960 w. w. SIMMONDS ETAL 2,931,628

WEIGHT CONTROL UNIT SYSTEM FOR DRILLING RIGS Filed Dec. 31, 1956 4Sheets-Sheet 1 \z INVENTOR.

Wayne W. Simmonds and Ar/ie J. Simmonds.

A TTORNEYS.

April 5, 1960 w. w. SIMMONDS ETAL 2,931,623

WEIGHT CONTROL UNIT SYSTEM FOR DRILLING RIGS Filed Dec. 31, 1956' 4Sheets-Sheet 2 INVENTOR. Wayne W. slmmondsw BY Ar/ie J.-5z'mm0nds.

A TTOHNEYE! April 5, 1960 w. w. SIMMONDS ETAL WEIGHT CONTROL UNIT SYSTEMFOR DRILLING RIGS Filed Dec. 51, 1956 4 Sheets-Sheet 3 d m R m mm m5 W mM Ar/z'e J. Simmonds A'T'TORNEKS.

April 5, 1960 w. w. SIMMONDS ET AL 2,931,628

WEIGHT CONTROL UNIT SYSTEM FOR DRILLING RIGS Filed Dec. 31, 1956 4Sheets Sheet 4 Ari/e J. -5immonds.

BY m w 3 www,

ATTORNEYS.

ited States WEIGHT CONTROL UNIT SYSTEM FOR DRILLING RIGS ApplicationDecember 31, 1956, Serial No. 631,918

1 Claim. (Cl. 254-173) This invention relates to weight control unitsfor rotary drilling rigs, and more particularly to control units forautomatically feeding the cable for lowering drill tools into a wellhole during drilling operations.

The principal objects of the present invention are to provide fluidcontrolled apparatus responsive to tension on a drilling cable forautomatically paying out said cable with drilling tools thereon as theformation is drilled; to provide apparatus with maximum sensitivity tovariation of the weight of the tools on the cable for varying thebraking of the cable drum whereby the cable is payed out from thewinding drum automatically to maintain substantially uniform pressure ofthe drill bit on the formation being drilled; to provide a closed liquidpressure system with a large cross section piston movable in response todeflection of the cable to move liquid in the system to a pressureresponsive member therein which varies the fluid pressure in apparatusthat actuates the winding drum brake; to provide such apparatus whereinthe pressure responsive member includes apparatus wherein operatingfluid flows through two orifices, one fixed and the other having aclosure associated therewith for varying flow therethrough, with aBourdon tube connected with the valve for controlling the extent ofclosure of said other orifice and the pressure of the operating fluid;to provide a drilling cable winding drum with a brake actuating memberthat is operated by fluid pressure to hold and pay out the cable tomaintain uniform weight acting on the drill bit with a cable tensionresponsive pressure medium for varying the operating fluid pressure.

In accomplishing these and other objects of the pres ent invention, wehave provided improved details of structure, the preferred forms ofwhich are illustrated in the accompanying drawings, wherein:

Fig. l is a partial perspective view of a drilling rig and derrick witha control unit embodying the features of the present invention.

Fig. 2 is a diagrammatic view of the control unit with portions brokenaway to illustrate the arrangement of components thereof.

Fig. 3 is a horizontal sectional view through a cable clamp member onthe line 33, Fig. 2.

Fig. 4 is a diagrammatic sectional view through a suitable conventionalrelay or pressure amplifier valve.

Fig. 5 is a perspective view of the pressure responsive orifice control.

Fig. 6 is a partial perspective view showing the adjustable fulcrum ofthe orifice valve.

Fig. 7 is a vertical sectional view tlmugh the fixed and controlledorifices of the signal pressure control.

Fig. 8 is a diagrammatic sectional view through a suitable pressureregulator.

Fig. 9 is a diagrammatic view of a modified form of control unit.

Referring more in detail to the drawings:

1 designates a portion of a drilling rig in connection with which ourinvention is adapted to be used and which atent ice includes a platform2 on which a derrick 3 is mounted. A crown block 4 is mounted on thederrick and has a drilling cable 5 reeved thereon, the cable 5 alsobeing reeved on a traveling block 6 provided with a hook 7 connected toa swivel 8 which in' turn is attached to a bail 9 of a swivel head 10 asin conventional practice. The swivel head is connected to a drill stem11 to which is attached a string of drill pipe and bit (not shown). Thedrill stem 11 extends through a rotary turntable 12 such as is usuallyemployed with drilling apparatus of this character. The cable. 5 has oneend dead ended or fixed relative to the derrick as, for example, bybeing attached to a derrick floor as indicated at 13 (Fig. l). The cableextends upwardly from the dead end and is reeved over the crown andtraveling blocks 4 and 6 and has its other end portion secured to andwound on a cable drum (not shown) in a drum housing 14 also mounted onthe derrick floor and provided with the usual operating levers 15, 16and 17, mounted upon a valve rack or board 18, as is common practice.

The weight control unit 19 includes a cable tension responsive member 20having a housing 21. The housing has a front wall 22 connected to sidewalls 23 which terminate in an outwardly extending flange 24 suitablysecured to a rear wall 25 by fastening devices 26. The rear wall 25 ismounted on a frame 27 having a boss 28 at the upper end thereof to whichan upper cable clamp structure 29 is connected. The lower end of theframe 27 has spaced arms 30 provided with aligned apertures 31 forrotatably mounting trunnions 32 of a pivoted member 41 secured to alower cable clamp member 33 whereby said lower cable clamp is pivotallymounted on the frame for swinging movement longitudinally relative tothe dead ended portion of the cable 5 to which the upper and lower cableclamp members are secured. Each of the cable clamp members 29 and 33include hook-like portions 34 extending from base portions 35 havingthreaded bores 36 therein. A clamp jaw 37, which in the illustratedstructure is a cap screw, is screwed into the threaded bores 36 wherebythe heads 38 of the screws cooperate with the hook portions 34' to clampthe cable 5 therebetween. The upper cable clamp member is arrangedwhereby the base portion 35 is slidably mounted in a socket 39 of theboss 28 and a suitable fastening device such as a screw 40 removablysecures said base member to the boss, as illustrated in Fig. 2. In thelower clamp member, the base member 35 is drawn against the pivotedmember 41 having the trunnions 32 thereon by means of a suitablefastening device such as a screw 42. A diaphragm 43 is arranged in thehousing 21 with the marginal portions of the diaphragm clamped betweenthe flanges 24 and the rear wall 25. The inner portion of the diaphragmis suitably secured to a plate 44 suitably secured to an axial stem 45slidably mounted in a bearing sleeve 46 in the front wall 22, the end ofthe stem having a head 4'7 adapted to engage the cable 5 between theupper and lower cable clamp members 29 and 33, as illustrated in Fig. 2.

The portion of the housing 21 between the diaphragm 43 and the rear wall25 defines a chamber 48 which is preferably filled with a liquid andcommunicates through a duct or pressure transmitting line 49 with apressure responsive member 50 which in the illustrated structure is aBourdon tube, the duct 49 being connected with the fixed end 51 of saidBourdon tube. With this arrangement, the tension responsive member 20 isactuated by variation in the tension on the cable 5 to transmit a signalpressure to the Bourdon tube 50. Gas could be utilized for the signaltransmitting media; however, it is preferred to use liquid for maximumsensitivity.

The Bourdon tube 50 is preferably arranged in a housing 52 mounted onthe board 18, which housing 52 also ie esneas preferably containsvarious valves of the control unit. A high pressure fluid line 53 leadsto the housing 52 from a suitable source of supply such as an aircompressor 53' and tank 53". The main high pressurefiuid line has abranch 54 to the inlet of a relieving type spring-loaded pressureregulator 55 which maintains a constant fluid pressure in'a duct or flowline 56, connecting the outlet of the regulator 55 with the inlet57 ofan orifice block 58 fixed on a bracket 59 in the'housin-g "52. Theregulator 55 is of a conventional type having a housing 120 with aninlet chamber121 receiving fluidpressure from the high pressure fluidline 54'. The'jinlet chamber communicates through a port 122 wi'th'anoutlet chamber 123 that is connected with thefflow line 6. The flowthrough the port "122 is controlledby a valve 124 having a stem 125engaged with a diaphragm 126 in a bonnet 127 whereby atmosphericpressure andpressure from a spring l28 act on'the diaphragm tending toopen the port 122 and pressurefrom the outlet chamber 123 passes throughan orifice 129 to act .on the other side of the diaphragm tending tomove the valve to close the port 122. The spring 128 is adjustedby ascrew 130 to set the pressure maintained 'in the flow line 56. Theorifice block 58 has an orifice '60 discharging into a chamber'61 whichhas an orifice'nozzle 62 discharging to the atmosphere, said orifice inthe nozzle 62 being larger than the orifice 60. The chamber 61hascommunication through a ductor flow line 63 to a relay valve 64. Therelay valve 6'4 may be any suitable relay or pressure amplifying valveand an example of such as'uitable conventional relay valve isillustrated in Fig. 4; however, the -structure per se of the relay valveis not the subject of the present invention. Afiapper or leaf'valve6'5has'one end positioned to-engage the end of the orifice nozzle 62 toclose same, a spring 66being connected to the 'fiappervalve and baseplate 59 to urge said end toward the "orifice nozzle. The other end ofthe flapper valve65 is connected as at 67 to the free or movable end ofthe'Bourdon tube 50. A bar 68 is supported'on the base member 59 andextends over the flapper valve and a fulcrum pin 69 is carried on abracket 70 adjustable longitudinally of the bar 68 and extendingdownwardly therefrom alongside of the flapper valve toprovidea fulcrumpin therefor. The fulcrum pin serves as a bearing point on which theflapper valve operates, and in effect, this pin is a proportional bandadjustment to vary the degree of angular movement of the free end 'ofthe flapper valve that engages the orifice nozzle. When the fulcrumtpinis toward .theffreei end of the Bourdon tube, the free end of theflapper valve willmovea greater distance, per unit change inthe Bourdontube tip movement than when the fulcrum pin is toward the orificenozzle.

The base plate or bracket 59 is pivotally mounted on a pivot member 71fixed to the housing 52 'and the portion of the base plate towards thefree end of the Bourdon tube is connected as at 72 with an adjustmentmechanism 73 on the housing 52 for pivoting or swinging the base plateabout the pivot member 71. Swinging the base plate to the right orclockwise (Fig. 2) about the pivot member 71 increases thepressure intheBour don tube required to operate the flapper valve and swingingsaid'base' plate counter clockwiseor to theflefttFigfQ) decreases thesignal pressure required. .The -.gas pressure is delivered tothemegulator'SS which preferably maintains approximately 20, pounds,pressure .at the fixed orifice 60. An increase in the signal pressurecauses the Bourdon tube to expand moving the free endof the tube to'theright (Fig. 2). This action causes the .fiapper valve'65 and orificenozzle 62 to act as a bleed valve bleedingj'pressure from the chamber 61by moving the flapper valve away from the orificenozzle 62 resulting ina leakage or-increase-of flow of gastherefrom with the resultantdecrease in the fluid pressure delivered through the line 63. A-decreaseinthe 'signahpressure .4 will cause the Bourdon tube to contract and thefree end of the tube to move to the left (Fig. 2). This action moves theflapper toward the nozzle causing a decrease in the leakage or flow ofgas from the nozzle opening and a build-up of pressure in the chamber 61and line 63, and if the nozzle is completely closed the pressure in theline 63 will increase to the maximum which is preferably-approximately20 pounds.

in order to provide for'operating the brake (not shown) forthe cabledrum tohold-orpay out the cable to the well hole, We provide afiuidpressurebrake actuator consisting of an extensiblemember .such asan air cylinder 75 having one end ,,pivotally connected to a bracket 76and having a piston rod"77extending from the other end thereofandpivotally connected as at 78 to a bracket 79 on a brake lever 80. Thebrake lever 80 has one end pivotally mounted on a pivot pin 81 of abracket 81 mounted on the platform 2. .An arm 82is fixed to said-one endof the brake lever 80 to. form a bell crank structure and said arm 82 isconnectcdto a suitable rod 83leading to the braking mechanism (notshown) connected to the cable drum, as is the usual practice. The brakelever is of substantial length with theother end provided with asuitably shaped handlel84 for an operator to hold and apply power tosaid lever Stifor manual operating of the cable brake mechanism whendesired. Afluid line 85 communicates with the lower end of the cylinder75 and.is connected with the outlet of a relieving type spring loadedpressure regulator 86, the inlet of said regulator being suppliedthrough a branch 87 connected with the main pressure supply line 53. Abranch 88 connects the main pressure supplyline with the inletof therelay valve 64, .the outlet of said valve being connected by a line 89communicating with the upper end of the cylinder (Fig. 2). ..A'doubleline three-way-valve 90 havinga control lever91 is interposed inthe lines and 89 between the pressure regulator .86 and relay valve 64respectively and the cylinder .75. The valve '90 is of conventionalstructure and is such that it normally provides for communication fromthe pressure regulator 86 and relay valve 64through the lines 85 and 89respectively to the cylinder. When it is desired to use the hand brakelevers 80, the'lever91 is moved to operate. the valve whereby. the'lines to-the regulator86 and relayvalve .64 .are closed .and the.linesfrom.the cylinder 75-.are vented to the atmosphere thereby removing .allpressure from. the cylinder 75 which would otherwise resist .-operationof thehand brakelever .80.

An exampleof ,a suitable. relay .orgpressure: amplifying valve .64is.illustrated in Fig. 94. It'js preferable that the pressureamplification be in. the order of-a ratio of 3 to 1.to. provide thedesired power. in the system. :The air line branch 88 has communicationwith the inlet chamber 95 and the line '89 has communication with theoutlet chamber 96. The body ofthe-valve has a chamber 97 and a chamber98 on oppositesides ofa diaphragm assembly 99. The operating air issupplied through the line 63 which communicates-with the chamber 97. Thechamber 98 communicates through a-small passage or tube 100 withtheoutlet chamber 96 whereby said pressure in the outlet chamber issupplied -to the diaphragm assembly 99. -When.theoperatingpressurethrough the line '63 is increased, the diaphragm assembly .99 is forceddownwardly, and through the relief valve 101 and. connecting tube 102the alveassemblylilli is-.forced.downwardly. to unseat same wherebyaairwill flow from the inlet chamber' 95 to the outlet chamber 96and throughthe line 89 to the cylinder 75 .until the pressure in the linc89zandapplied through the tube 100 to the chamber'98 arrivesiat a pressurenecessary to balance thediaphragm 99 to close the valve assembly 103. Ifthe pressure supplied; through the line 63 to the chamber 97isdecreased, thepressure in the chamber 98, whichcisthesameas thepressure in the line 89, unbalances thediaphragm 99-to movesame upg.'w'ardly to open the relief valve 101 whereby air pressure is bled fromthe chamber 96 through the relief valve opening, raising the reliefpoppet assembly 104 whereby said air is bled through the ports 105, 106and 107 to the atmosphere until the pressures acting on the diaphragm 99are again in balanced position to efiect closing of the relief port.

The pressure in the inlet chamber 95 acts on a balanced diaphragm 108and a pilot diaphragm 109 is acted on by pressure in the pilot chamber110 which communicates through passage 111 with the space between therelief valve 101 and the relief poppet assembly 104. In accordance withthe designed ratio of pressure amplification, increase of pressurethrough the line 63 effects a corresponding ratio of increase ofpressure in the line 89 and adecrease in pressure in the line 63 effectsa decrease in pressure in the line 89 in accordance with said ratio.

In operation of an apparatus constructed and assembled as described, thedrill stem and drill bit are lowered into the hole and during thelowering operation the entire weight of the stem and bit are on thecable. When the drill bit reaches the bottom of the hole, a portion ofthe weight will be supported by the formation, and it is desirable thatthe weight of the bit and stem supported by the formation be retainedwithin certain limits and that the remainder of the weight be supportedby the cable 5. The portion of the weight of the drill stem and toolssupported by the cable is determined by the pressure shown on a gauge(not shown) usually present in drilling apparatus of this character. Theadjusting mechanism 73 of the base plate 59 is then moved until theflapper valve closes the nozzle 62 when the portion of the weightsupported by the cable is at a predetermined minimum for drillingoperations and the flapper valve in nozzle opening position when theportion of the weight supported by the cable is at a predeterminedmaximum. Air from the pressure supply is then delivered through the line53, branch 87 to the pressure regulator 86 and line 85. Air also flowsthrough the branch 88 to the relay valve 64 and through branch 54,pressure regulator 55, line 56, to the orifice block 58, through theorifice 66 into the chamber 61. The valve lever 91 is then operated toopen the valve 90 whereby the pressure determined by the setting of thepressure regulator 86 is supplied through the line 85 to the lower endof the cylinder 75. Air flows through the line 89 from the relay valve64 to the upper end of the cylinder 75. Assuming the weight on the cableis at the minimum desired, the pressure transmitted by the diaphragm 43to the liquid between said diaphragm and the rear wall 25 of the housing21, is transmitted through the line 49 to the Bourdon tube 50 whichresponsive to said pressure moves the flapper valve 65 into closingposition relative the nozzle 62. The pressure in the chamber 61 thenbuilds up to that set by the regulator 55 and applies said pressure tothe diaphragm assembly 99 of the relay valve 64 opening the valveassembly 163 whereby air pressure flows from the branch 88 through therelay valve and line 89 to the cylinder 75 to apply pressure to theupper portion of the piston in the cylinder 75 to move the brake lever80 to apply the brake on the cable drum. Then as drilling operations arecontinued, the proportion of the weight of the drilling tools supportedon the cable 5 tends to increase as the formation is drilled. Thisapplies an increased tension to the cable which reduces the deformationthereof forcing the plunger 4-5 and diaphragm 43 to increase thepressure on the liquid thereby and accordingly the pressure of theliquid in the Bourdon tube 50. This increase in pressure in the Bourdontube tends to straighten same, moving the flapper valve 65 away from thenozzle 62 to increase the eifective size of the orifice therein untilmore air can flow through the nozzle 62 than flows through the orifice60 thereby decreasing the pressure in the line 63 and acting on thediaphragm assembly 99. The decrease in the pressure acting on thediaphragm assembly 99 causes a proportionate decrease in the pressureacting on the upper portion of the cylinder 75. The pressure acting onthe lower end of the cylinder remains constant; therefore, as thepressure on the upper end of the cylinder 75 is decreased, the brakingaction on the cable drum is reduced until it allows the paying out ofsome cable. As the cable is payed out, the portion of the weightsupported by the cable is reduced in reducing the pressure of the liquidacting on the Bourdon tube whereby the flapper valve decreases the sizeof the orifice in the nozzle 62 causing an increase of pressure actingon the diaphragm assembly 99 and a proportional increase of pressureacting on the upper portion of the cylinder 75 to tighten the brake onthe cable drum to stop paying out of cable therefrom. The change ofpressure on the liquid in the Bourdon tube in response to change oftension on the cable is such that the apparatus is very sensitive,providing a substantially balanced condition whereby the brake on thecable drum is applied with only sufficient pressure to retard rotationof the drum and maintain a substantially constant portion of the weightof the drill string on the cable, with substantially continual rotationof the drum as the formation is cut away. The use of the orifices in theorifice block controlled by the Bourdon tube is such that the operationof the relay valve is relatively slight, providing a smooth evenapplication and release of the brake, eliminating substantially allhunting for the proper Weight and also eliminating substantially all ofthe jerking of the cable and tools that would result from such hunting.

In the form of the invention illustrated in Fig. 9, a spring 112 issuitably connected in the brake actuating structure, as, for example,from the brake lever 86 to the platform 2, whereby the spring urges thebrake lever into brake applying position. A cylinder 113 has a pistonplunger 114- extending from the lower end and connected to the brakelever by the bracket 79. The upper end of the cylinder is connected tothe bracket 76. The upper portion of the cylinder has a port 115 openingto the atmosphere. The lower end of the cylinder is connected by a line116 through a valve 117 and line 118 to the relay valve 64. The valve117 is similar to the valve but operating only on one line whereby whenthe valve is closed no air flow will occur through the line 113, and theline 116 will be opened to the atmosphere for manual operation of thebrake lever 86, and when the valve 117 is open, the flow of air is fromthe line 118 through the valve 117 and through the line 116 to the lowerend of'the cylinder 113. The orifice body 53 of the pressure responsivemechanism is arranged on the op posite side of the flapper valve as inthe form shown in Fig. 2, whereby, in the modified form, increasedpressure in the Bourdon tube moves the flapper valve to decrease thesize of the orifice of the nozzle and increase the pressure appliedthrough the line 63 to the relay valve 64. In this form of theinvention, lessening or reduced weight on the cable 5 reduces thepressure acting in the Bourdon tube 50 whereby the flapper valve 65 ismoved to increase the effective orifice of the nozzle 62, reducing thepressure in the chamber 61 and correspondingly reducing the pressureapplied to the diaphragm assembly 99 in the relay valve 64. This effectsa reduction in pressure applied to the lower portion of the cylinder 113whereby the spring 112 tends to overcome said pressure and apply thebrake to stop or slow down the paying out of cable from the cable drum.As the tension on the cable increases, due to increased portion of theweight being supported thereby, the pressure inthe Bourdon tubeincreases, reducing the elfective size of the orifice in the nozzle 62to cause a build-up of the pressure in the chamber 61 and acorresponding build-up of the pres- ,sure acting on the diaphragmassembly 99 of the relay valve 64 and a proportional increase in the airpressure flowing through the relay valve and line 116 to the cylinder113 to overcome the spring 112 and reduce the presassume sure of. thebrake on the cable: drum thereby payingout more ofthe cable therefrom. I

Itwillzbe obvious v from the foregoing thatiwethave provided an improvedapparatus for controlling ,thetpaying out of. drilling:,cable tin avdrilling rig foriautornatic operation, substantially maintaining aconstantpressure of the drill bit on the formation being drilled.

ltis to be understood thatwhile we haveuillustrated and describedcertainiforms of our invention,.:it is not to belimited to the specificforms or arrangement of parts herein described andshown except insofaras such limitations are included in the claim. 7

What we claim and desire to secure by Letters Patent A control unit forautomatically varying the paying out of cable from a brake restrainedcabledrum in response toivariation in tension of the cableidue to theproportion of the weight of well drilling-toolszsupported by the cabletending to unspool the cable from the cable drum comprising, a brakelever connectedwith the cable drum brake for moving said brake from.cable drum holding position to cable drum releasingipositioma .fluidpressure responsive brake actuator connected with-the brake lever, afluid pressure supply of greater pressure than is required for the fluidpressure responsive brake actuator, means connected with the brake leverto urge the brake into cable drum holding position, a fluid conductingmeans connecting the fluid pressure supply with the fluid pressureresponsive brake actuator to move th brake lever and actuate the brakeinto drum releasing position, control valvemeans in said fluidconducting means and operable to selectivelyshut ofli the fluid pressuresupply,to saidpressure responsive brake actuator and release pressurefrom said actuator whereby the brake is urged to cable drum holdingposition, a relay valve in said fluid conducting means upstream fromsaid control valve for regulating the pressure delivered thereby to saidfluid pressure responsive brake actuator, asecond fluid conducting meansconnecting the fluid pressure supply with the relay valve for providingan operating pressure therefor, a pressure regulator in the second fluidconducting means for regulating the maximum operating pressure deliveredto the relay valve, orifice means in the second fluid conducting meansdownstream from the pressure regulator. for limiting flow through saidsecond fluid gconducting means, a second orifice of largencapacity thanthe first-named orificeand communicating the-second fluid conductingmeans between the'firstnamed orifice and the relay valvewith theatmosphere, a valve member movable toward and away from the second-namedorifice to vary the discharge therefrom, a Bourdon tube havingone endfixed relative to said second fluid conducting means and a free endconnected with the valve member, a frame having spaced portions one ofwhich is fixed to the cable remote from the cable drum and the otherportion movably connected to'said cable whereby said cable is movablerelative to the frame in response to change oftension of said cable, acylinder on the frame, means in the cylinder defining a liquidcontaining chamber, means communicating the liquid containing chamberwith a fixed end of the Bourdon tube, and means extending from thecylinder and engaging the cable. whereby change of tension in the cablechanges the capacity of the liquid containing chamber and effectsReferences Cited in the file of this patent UNITED STATES PATENTS2,117,078 Brauer May 10, 1938 2,455,917 Crake Dec. 14, 1948 2,759,702Abraham Aug. 21, 1956 FOREIGN PATENTS 394,991 Great Britain July'4, 1933OTHER REFERENCES La Joy: Industrial Automatic Controls, published byPrentice-Hall (New York) 1954, pages l20l24 relied on. (Copy inScientific Library of the Patent Oflice Card No. TJ 214L24.)

